This is a common problem for people with 1920 x 1080 resolution monitors. Quick Launch icon are just too small. You can fix this by right click on an empty space in Taskbar and uncheck “Lock the Taskbar”.

Note: If it is already unchecked skip this step 🙂

Now go to the Quick Launch drag handle and right click exactly on it.

Just select “Large Icons” and icons in Quick Launch bar will be increased. After that you can check “Lock the Taskbar” option if it was checked prior.
Easy, isn’t it 🙂 And it’s very helpfull to have large icons in Quick Launch bar.